Calcific chronic lateral epicondylitis: a histological and ultrastructural study.

Fragments of insertion tissue from right arm common extensor muscle have been collected from a 25-year patient with chronic lateral epicondylitis. Specimens, processed for light (LM) and electron (EM) microscopy, evidentiated a variety of degenerative alterations, such as focal hyalinosis, lipoidosis, collagen fiber redistribution, calcifications and vascular changes. Evidence of collagen normal function maintenance and turnover have been also observed in tenocytes.